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Phosgene Gas

I find that I'm often exposed to phosgene gas when welding. There's usually residual gas in pipes when I'm servicing equipment that produces phosgene when heated. I'm wondering if anyone has any advice for me to help deal with this unpleasant and potentially harmful event? Do any of you guys use a mask?

Dixie, I would suggest changing your evacuation habits. I lost a buddy of mine about 15 years ago to phosgene gas poisoning, he got in a hurry, breathed a bunch of it, walked around for a week feeling terrible, doc told him it was the flu. His wife found him dead on the kitchen floor the next morning. 27 years old with a wife, a 3 year old and one on the way, wife lost the baby a few weeks later. Something to think about.

If you have a good reclaim unit and do a double evac you should never have to worry about phosgene,I have welded on some pretty big lines and have not been exposed, the only time I ever have been is when I cut corners.

Phosgene, we like you, we just can’t stand the smell of you, that’s all.

Most of us already know that phosgene gas is a byproduct of some refrigerants when they are exposed to an open flame, or extreme heat. We also know that this byproduct is extremely dangerous, even in small trace amounts. Since we cannot remove the open flame, or extreme heat needed to braze our systems, we need to do the next best thing, remove the potential of these refrigerants from reaching the open flame, or extreme heat.

This isn’t always entirely possible based on the fact that small amounts of trapped refrigerant can linger in small amounts of refrigeration oil that is pooled inside our refrigeration circuit. But as already been pointed out, good refrigerant recovery procedures and practices can reduce our potential of coming into contact with this extremely dangerous byproduct.

Good and sound recovery practices, its good for the environment, and good for us as well.

I read an article on Phosgene gas that says the only refrigerant that creates "true" Phosgene gas is R-12. The gas produced by R-22 is similar and Harmful, but is not really phosgene. Im just quoting this, not sure how true it is.

I found the proof

Being extremely toxic in small amounts, phosgene formation was a real concern when traditional refrigerants (R11, R- 12, R- 113, R- 114) decomposed. Phosgene contains two chlorine atoms and an oxygen atom. It will only form when oxygen is present and only the refrigerants with chlorine attached will produce phosgene (not HFCs). R22 has only one chlorine atom per molecule, so it is extremely difficult, chemically speaking, to get another one attached to form phosgene. Decomposition of R-22 or HFCs may form other carbonyl fluorides, however they are not as toxic as phosgene.

I started out in this trade repairing through the wall units way before recovery. We would blow the charge and un-sweat the compresor. 9 times out of 10 you would get a face full of phosgene and gag the hell out of ya. Normal hazzard of the job then with a cancer stick in my mouth. If I only knew then what I know now........